This invention relates generally to manufacturing techniques, and more specifically to methods and apparatus for securing and forming components for manufacture.
Accurate manufacturing of a component may be a significant factor in determining a manufacturing time of the component. Specifically, when the component is a gas turbine engine transition piece, accurate manufacturing and/or reforming of the transition piece may be a significant factor affecting an overall cost of fabrication or maintenance of the gas turbine engine, as well as subsequent modifications, repairs, and inspections of the transition piece. For example, at least some known gas turbine engine transition pieces have a complex geometrical shape at an aft-end of the transition piece which enables the aft-end to mate with a component called a picture frame.
During initial manufacture, transition piece blanks fabricated to near-specification dimensions are supplied to a finishing process that shapes the transition piece to the close tolerances required by the manufacturing process quality control. The transition piece may also be a component that has been used in an operating gas turbine and returned to a shop to correct a deformation condition known as thermal creep. More specifically, during operation at elevated temperatures, the transition piece may deform from the engineering design specification dimensions. Maintenance procedures may then be required to return the transition piece dimensions to design specification dimensions.
At least some known manufacturing processes used with transition pieces may be substantially manual, such as, through the use of a ball peen hammer, manual pump hydraulic jack, and acetylene torch to physically form the aft-end of the transition piece. However, such methods may create irregularities in the transition piece shape, specifically in the corners, leading to mismatches in the flow path from the transition piece body to the picture frame. The hydraulic jacking method creates irregularities in the inner and outer rails due to the point loading that occurs when using manual hydraulic jacks. Often, the mismatched components do not meet specific engineering specifications, resulting in a defective part. The ball peen hammer may also create a thinning of the parent metal in the corners. Tools, such as, an ID profile gage, have been developed to improve dimensional accuracy and assist in the manufacturing process. The ID profile gage may be inserted into the mouth of the aft-end of the transition piece and the transition piece body formed with a hammer or hydraulic jack to match the contour of the gage. However, such tools generally do not improve the throughput of transition pieces through the process, and may cause flatness defects due to additional machining that may be necessary after using such techniques.